When the Washington Nationals walked down the south side steps of the White House Monday for a ceremony honoring their World Series win, they were accompanied by a musical number not commonly played by the U.S. Marine Band. Yes, they walked out to singalong tune “Baby Shark.”

For many Americans not following the Nationals season, the song came out of left field when the baseball team made the World Series. 

However, the children’s song had steadily been chomping its way into the hearts of Nationals fans since mid-June, when outfielder Gerardo Parra made it his walk-up song.

Parra told NBC Sports Washington in August that “his 2-year-old daughter joined the long line of children charmed by the song’s relentless simplicity.”

Calling the song an “infectious earworm,” Scott Allen of the Washington Post explains, it was an “old campfire ditty that was reinvented by Korean children’s entertainment brand Pinkfong in 2015 and grew into a cultural phenomenon last year.”

Reinforced by the team’s rise to the playoffs, the song became an unofficial rallying cry through the fall.

What was once the off-beat track for a single Nationals pinch hitter, solidified itself even more Monday as a team anthem as they walked down the White House steps for the official tribute.